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A new mineral bettertonite (IMA 2014-074), ideally [Al6(AsO4)3(OH)9(H2O)5]·11H2O, was discovered at the Penberthy Croft mine in ~1.5 km from the village of Goldsithney, St. Hilary, Cornwall, England, U.K. (50.1414°N 5.4269°W). The mine is well known as a source of rare secondary CuPbFe arsenates and was classified in 1993 as an SSSI (Site of Special Scientific Interest). Bettertonite occurs in quartz veins closely associating with arsenopyrite, chamosite, liskeardite, pharmacoalumite, pharmacosiderite and minor brochantite, chalcopyrite and cassiterite. Much of supergene alteration is post mining. The new mineral along with liskeardite was probably formed from leaching and the replacement of Al to Fe in pharmacosiderite, Bettertonite forms bright white, lustrous, ultra-thin (sub-micrometer) blades, sprays and laths with lateral dimensions <20 μm, or their radiating groups that line and infill interconnecting and isolated cavities (14 mm) in quartz and chamosite. The laths are flattened on {010}; other forms are {010}, {100}, and {001}. Bettertonite is translucent with a white streak and a vitreous to pearly or silky luster. The cleavage on {010} is perfect. The density was not measured due to the thinness of the crystals; Dcalc = 2.02 g/cm3. The mineral is nonpleochroic, optically biaxial (+) with α = 1.511, β = 1.517, γ = 1.523 (white light), 2Vcalc = 60.2°; X = c, Y = b, Z = a. The average of 4 electron probe WDS analyses [wt% (range)] is: Al2O3 35.8 (34.5–36.1), Fe2O3 2.45 (1.93–2.82), As2O5 36.5 (35.6–37.7), SO3 2.19 (1.18–2.60), Cl 0.56 (0.29–0.89), O=Cl2 0.13, total 77.47. Normalized to a total of 100% when combined with the H2O calculated based on structure analysis: Al2O3 29.5, Fe2O3 2.0, As2O5 30.1, SO3 1.8, Cl 0.5, H2O 36.2. The empirical formula, based on 9 (Al+Fe+As+S) pfu is Al5.86Fe0.26(AsO4)2.65(SO4)0.23 (OH)9.82Cl0.13(H2O)15.5. The strongest lines in the powder X-ray diffraction pattern are [d Å (I%; hkl)]: 13.65 (100; 011), 13.51 (50; 020), 7.805 (50; 031), 7.461 (30; 110), 5.880 (20; 130), 3.589 (20; 202); 2.857 (14; 182). The monoclinic unit-cell parameters refined in space group P21/c from the powder X-ray data are a = 7.788(3), b = 26.957(7), c = 15.925(8) Å, β = 93.9(1)°, V = 3336 Å3. The refinement of single crystal data collected at 100 K on the microfocus beamline MX2 at the Australian Synchrotron (λ = 0.71073 Å) on a rectangular lath (20×10×1 μm) yielded R1 = 0.083 for 2164 observed [I > 2σ(I)] reflections. The singlecrystal unit-cell parameters are: a = 7.773(2), b = 26.991(5), c = 15.867(3) Å, β = 94.22(3)°, V = 3319.9 Å3, Z = 4. Bettertonite is a natural example of a polyoxometalate (POM) compounds. It has a heteropolyhedral layered structure, with the layers parallel to (010). The layers comprise hexagonal rings of edge-shared AlO6 octahedra that are interconnected by sharing corners with AsO4 tetrahedra. The layers are strongly undulating and their stacking produces large channels along [100] that are filled with water molecules. These polyoxometalate clusters, of composition [AsAl6O11(OH)9(H2O)5]8–, are interconnected along [100] and [001] by corner-sharing with other AsO4 tetrahedra. The mineral honors John Betterton (b. 1959) a museum geologist/mineralogist at Haslemere Educational Museum, Haslemere, Surrey, U.K., for his extensive contributions to the characterization of minerals from the Penberthy Croft mine. Cotype specimens are deposited in the Museum Victoria, Melbourne, Victoria, Australia, and in the Natural History Museum, London, U.K. D.B.

The new mineral bobshannonite (IMA 2014052), ideally Na2KBa(Mn, Na)8(Nb, Ti)4(Si2O7)4O4(OH)4(O, F)2, was discovered in the pegmatite from a blast pile at the Poudrette quarry, Mont Saint-Hilaire, Québec, Canada. The type specimen is 2.5×2.3×2 cm and consists mostly (~90%) of sérandite. Orange-brown blocky crystals of bobshannonite up to 0.51 mm are perched on sérandite and albite. Other associated minerals are epididymite (rich), catapleiite, aegirine (2 generations), kupletskite, rhodochrosite, and rhabdophane-(Ce) and undetermined botryoidal Mn oxide. The mineral is of hydrothermal origin. The main forms of euhedral crystals of bobshannonite are {001}, {110}, {110}, and {010}. The mineral is vitreous to frosty, transparent to translucent pale brown (in small fragments) to orange brown with a very pale brown streak and hackly fracture. Cleavage is perfect on {001} and no parting was observed. It does not fluoresce under cathode or UV rays. The mineral is brittle with a Mohs hardness ~4. The density was not measured; Dcalc = 3.787 g/cm3. Crystals of bobshannonite are extensively twinned and do not extinguish in cross-polarized light. That did not allow to obtain data on optical properties. The mineral is non pleochroic in the cleavage plain, but change color from colorless to brown in other sections. The FTIR and Raman spectra show a strong peak at 3610 with a weak shoulder at 3655 cm–1 assigned to the stretching vibrations of OH groups. A strong peak at 901 cm-1 and medium- to low-intensity peaks at 1038, 970, 716, and 680 cm-1 on the Raman spectrum may be assigned to Si–O stretching vibrations of the Si2O7 groups. Peaks at 608, 580, 510, and 410 cm-1 correspond to bending vibrations of Si2O7 groups and those at 341, 310, 240, 207, and 143 cm-1 to the lattice modes. The average of 9 electron probe WDS analysis (ranges are not given) is (wt%): Ta2O5 0.52, Nb2O5 19.69, TiO2 5.50, SiO2 26.31, Al2O3 0.06, BaO 7.92, ZnO 1.02, FeO 0.89, MnO 26.34, MgO 0.06, Rb2O 0.42, K2O 2.38, Na2O 4.05, F 0.70, H2O (calculated using structure data) 1.96, O=F2 0.29, total 97.53. The empirical formula based on 38 (O+F) is Na1.89(K0.93Rb0.08)∑1.01Ba0.95(Mn6.85Na0.52Zn0.23Fe0.232+Mg0.03Al0.02)∑7.88 (Nb2.73Ti1.27Ta0.04)∑4.04 (Si8.07O28)O9.32H4.01F0.68. The strongest lines in the powder X-ray diffraction pattern [d Å (I%; hkl)] are: 2.873 (100; 2 41,241,044,044,241,241), 3.477 (60; 006), 3.193 (59; 224,224), 2.648 (40; 402,243,243), 2.608 (35; 008,226,226), 1.776 (30; 249). The triclinic unit-cell parameters (space group C1¯) refined from the powder X-ray data are a = 10.826(5), b = 13.896(6), c = 20.946(7) Å, α = 90.00(3), β = 95.01(3), γ = 90.00(3)°, V = 3139 Å3. The single crystal unit-cell parameters are a = 10.839(6), b = 13.912(8), c = 20.98(1) Å, α = 89.99(1), β = 95.05(2), γ = 89.998(9)°, V = 3152 Å3, Z = 4. The crystal structure was refined to R1 = 2.55% for the space group C1¯ on the basis of 7277 unique [F > 4σ(F)] reflections and can be described as a combination of a titanium silicate (TS) block and an I (Intermediate) block. The TS block consists of HOH sheets (H = heteropolyhedral, O = octahedral). The topology of the TS block is as in Group II of the Ti disilicates: Ti + Nb = 2 apfu per (Si2O7)2 (Sokolova, 2006). In the O sheet, ten MO octahedra form a close-pack and are occupied mainly by Mn, less Na and minor Zn, Fe2+, Mg, and Al. The Si2O7 groups and MH octahedra occupied by Nb and Ti (Nb > Ti) share common vertices to form the two identical H sheets. An O sheet and two adjacent H sheets link through common vertices of SiO4 tetrahedra and MH and MO octahedra to form a TS block parallel to (001). The TS blocks link via common vertices of MH octahedra. In the I block, Ba and K are ordered at the peripheral AP(1) and AP(2) sites with Ba:K = 1:1 and the two BP sites are occupied by Na. The ideal composition of the I block is Na2KBa apfu. Bobshannonite, perraultite, surkhobite, and jinshajiangite are topologically identical Group-II TS-block minerals. Bobshannonite is the Nb-analog of perraultite. The mineral honors Robert (Bob) D. Shannon (b. 1935), in recognition of his major contributions to the fields of crystal chemistry and mineralogy through his development of accurate and comprehensive ionic radii and his work on dielectric properties of minerals. The holotype specimen has been deposited at the Canadian Museum of Nature, Ottawa, Canada. D.B.

Lukkulaisvaaraite (IMA 2013-015), ideally Pd14Ag2Te9, is a new mineral found at the Lukkulaisvaara intrusion, northern Karelia, Russia. The mineral occurs with other platinum group element (PGE) minerals in gabbronorite from the Early Proterozoic Lukkulaisvaara layered intrusion. The mineral formed under post-magmatic conditions below 600 °C and was found rimmed by tulameenite and accompanied randomly by telargpalite and Bi-rich kotulskite, enclosed within chalcopyrite in association with millerite, bornite, hematite, moncheite, tulameenite, hongshiite, telluropalladinite, sperrylite, palarstanide, and polymineralic platinum-group mineral grains. Lukkulaisvaaraite is opaque with gray streak, a metallic luster and is brittle. The micro-indentation hardness VHN20 =355 (339–371) kg/mm2, corresponds to ~4 of a Mohs scale. In plane-polarized light, lukkulaisvaaraite is light gray with a brownish tinge, has strong bireflectance, light brownish-gray to grayish-brown pleochroism. Anisotropy is distinct to strong. No internal reflections were observed. Reflectance values were measured in air between 400 and 700 nm in 20 nm intervals. The values for COM wavelengths [Rmin, Rmax % (λ nm)] are: 40.9, 48.3 (470); 47.6, 56.4 (546); 52.1, 61.0 (589); 57.5, 65.2 (650). The average of 5 electron probe WDS analyses is [wt% (range)]: Pd 52.17 (51.06–53.27), Ag 7.03 (6.26–7.69), Te 40.36 (39.77–41.23), Bi 0.05 (0.03–0.09), total 99.61. This gives the empirical formula Pd14.05Ag1.88Te9.06 based on 25 apfu. The strongest lines in the X-ray powder-diffraction pattern of synthetic lukkulaisvaaraite [d Å (I%; hkl)] are: 2.832 (58; 130,310), 2.809 (92; 213), 2.554 (66; 312), 2.431 (41; 321,231), 2.137 (57; 411,141), 2.1015 (52; 233,323), 2.045 (100; 314), 2.003 (63; 420,240), 1.970 (30; 006), 1.405 (30; 246,426), 1.319 (36; 543,453). The crystal structure was solved and refined from the powder X-ray diffraction (XRD) data of synthetic Pd14Ag2Te9. The mineral is tetragonal, space group I4/m, with a = 8.9599(6), c = 11.822(1) Å, V = 949.1 Å3, and Z = 2. Lukkulaisvaaraite has a unique structure type and shows similarities to that of sopcheite (Ag4Pd3Te4) and palladseite (Pd17Se15). The structure can be viewed as a three-dimensional framework composed of two types of blocks of polyhedra interconnected by common Te atoms. There are four independent metal sites (M1–M4) and two Te sites where M(1) can be viewed as in transition between tetrahedral and square planar, M(2) and M(3) are at the centers of rectangles formed by Te atoms and where M(4) site is surrounded by four M(1) and four M(2) sites in a distorted square antiprismatic coordination. The mineral is named for the type locality. The holotype is deposited in the Department of Mineralogy of the National Museum, Prague, Czech Republic. O.C.G.

Möhnite (IMA 2014-101), ideally (NH4)K2Na(SO4)2, is a new supergene mineral found in a guano deposit on the Pabellón de Pica mountain, near Chanabaya, Iquique Province, Tarapacá Region, Chile e (20°55′ S, 70°08′ W), which is of particular interest from the viewpoint of the behavior of copper in lithospheric processes, being the type locality of several N-bearing and organic copper minerals, where chalcopyrite served as source for copper. Associated minerals are salammoniac, halite, joanneumite, natroxalate, nitratine, chanabayaite, and a clay mineral. Möhnite crystals overgrow crystalline crusts of salammoniac and encrust cavities in salammoniac aggregates and form random aggregates and clusters (up to 1 mm across), as well as crusts consisting of imperfect bipyramidal, light brown to brown spindle-shaped crystals up to 0.07×0.07×0.15 mm in size. It does not exhibit fluorescence under UV light. It is brittle with no cleavage observed and Mohs hardness is 3. Dmeas = 2.4(1) (measured by flotation in heavy liquids) and Dcalc = 2.461 g/cm3. Möhnite dissolves in water but is stable in dry air. Under plane-polarized light möhnite is light brownish-yellow and non-pleochroic. In crossed nicols it looks isotropic. The mineral is optically neutral, with ε and ω = 1.505(2) (λ = 589 nm). FTIR spectrum of möhnite shows bands at (cm-1; s = strong, m = medium; w = weak): 3240m, 3076m, 2150w, 2078w, 1431, 1165s, 1111s, 988m, 836w, 775w, 619s, 555w, 519w, 450w. Band assignment are in agreement with the presence of NH4+ and SO4 groups. Bands in the range from 1500 to 1700 cm-1 that could belong to H2O molecules are absent in the IR spectrum of möhnite. Average of electron probe EDS analyses (using rastered 8×8 μm beam; number of analyses not reported) is [wt% (range)]: (NH4)2O 7.99 (N by gas chromatography, H by stoichiometry), Na2O 9.49 (8.98–9.94), K2O 32.34 (31.89–32.79), SO3 51.32 (50.76–51.92), total 101.14 wt%. The empirical formula, calculated on the basis of 8 O apfu is: (NH4)0.95Nao.95K2.14S1.99O8. The strongest X-ray powder diffraction lines [d Å (I%; hkl)] are: 4.955 (27; 100), 4.122 (37; 101,011), 3.708 (29; 002), 2.969 (74; 102,012), 2.861 (100; 110), 2.474 (20; 003), 2.060 (33; 022). Unit-cell parameters refined from the powder data are: a = 5.732(1), c = 7.425(1) Å, V = 211.3 Å3. Refinement of X-ray diffraction data collected on a single-crystal (0.11×0.13×0.15 mm) yielded R1 = 0.0492 for 241 unique F > 4σ(F) reflections. Möhnite is trigonal, P3¯m1, with unit-cell parameters of a = 5.7402(3), c = 7.435(1) Å, V = 212.16 Å3, Z = 1. Möhnite belongs to the aphthitalite group and is isostructural with aphthitalite, K3Na(SO4)2. The fundamental building block of the aphthitalite structure is a layer consisting of vertex-connected NaO6 regular octahedra and SO4 tetrahedra. Larger cations (NH4+ and K) are ordered in two sites (a 10-vertex and a 12-vertex polyhedra), one of which is attached to the layer; the other is situated between the layers. Möhnite is the first NH4+-dominant member of the aphthitalite group. A mineral with 5.68 wt% (NH4)2O and 33.87 wt% K2O from the Guañape Islands, Peru, was described by Frondel (1950) as an ammonium variety of aphthitalite. The crystal structure of this mineral was not investigated, but according to chemical data it may be an ammonium-deficient variety of möhnite. The mineral is named in honor of the prominent German amateur mineralogist and mineral collector Gerhard Möhn (b. 1959), coauthor of descriptions of several new mineral species. The holotype specimen is deposited in the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia. F.C.

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